The proposed work is concerned with the effect of progesterone and androstendione on ovarian function. Constant infusion of these steroids to reproduce circulatory levels of these steroids as observed from ACTH stimulation of adrenal cortex will be carried out and the effect on ovulation and the subsequent luteal formation and function will be observed. Measurement of plasma levels of LH, estrogen and progesterone will be done to monitor pituitary and gonadal function. Studies will also be done to determine the relationship between adrenal function and LH secretion in suckled rats. BIBLIOGRAPHIC REFERENCES: Adrenallctomy and pituitary LH in the oophorectomized suckled rat. 1974. E. Landers and W. C. Wagner. Acta Endocrin. Kbh. 77:498-501. Effect of local or parenteral application of ACTH or Hydrocortisone on Bovine CL Function. 1976. W. C. Wagner, R. E. Strohbehn and P. A. Larson. Acta Endocrin. In press.